The Ravens got center Matt Birk back on the practice field this morning, but several other key contributors were absent.

Kicker Billy Cundiff, who was on the injury report for the first time yesterday with a sore left calf muscle, was not practicing in the portion open to the media. We should know more about Cundiff's injury when Ravens coach John Harbaugh meets with the media later today.

Linebacker Ray Lewis, who has not been practicing even on a limited basis since leading up to the San Francisco 49ers game, also was absent. It's expected that Lewis will miss his fourth consecutive game with a toe injury, though the Ravens haven't ruled him out yet.

Cornerback Chris Carr has missed two straight games with a back injury and it appears that he'll miss Sunday's game against the Indianapolis Colts, Carr hasn't practiced all week.

Birk's presence on the practice field, however, is good news for the Ravens. He missed one series against Cleveland last Sunday with a right shoulder injury, but he returned and finished the game. Today marks the first time this week where he's been an active participant in practice.

Guard Ben Grubbs, who missed Wednesday's practice with a toe issue, also was participating in this morning's practice.